Counterbalance for vertically sliding doors



March 19, 1940.. H. QBLODGETT 2,194,111

I COUNTERBALANCE FOR VERTIGALLY SLIDING DOORS Filed May 29, 1959 INVENTOR.

ATTORNEYS Patented Mar. 19, 1940 COUNTEBBALANOE FOB VEB'I'ICAILY ING DOORS Herbert Cady Blodgett, Hartford City, Ind., u-

lignor to Overhead Door Corporation, Hartford City, Ind.

Application May-29, 1939, Serial no. 210,310

Claims.

This invention relates to improvements in counterbalance for vertically sliding doors. The main objects of my invention are: First, to provide a counterbalancing mechanism of the torsion type for vertically operated doors whereby the pitch lead of the counterbalance cable is automatically altered during counterbalancing of the door to enable the latter to be retracted further than has heretofore been possible.

Second, to provide a counterbalancing device for vertically operated doors, wherein the counterbalance unit is shifted automatically under the influence of the door movement.

Third, to provide a counterbalancing device which reduces the required head room in vertically sliding door installations.

' Fourth, to provide the combination of a counterbalancing device having the advantages described above with a vertically operable door hav ing an inclined vertical track.

Fifth, to provide a counterbalanced device which may be easily erected or assembled on vertically operating doors already installed, to enable the bottom section of the door to be raised to a position above, the header, thereby increasing the effective height of the door opening.

Further objects relating; to details and economies of my invention will definitely appear from the description to follow. The invention is defined in the claims. i I

A structure embodying the features of my invention is illustrated in the accompanying draw- .ing, wherein: Fig. l is a fragmentary view in side elevation of. a vertically operating door installation provided with the counterbalance of my invention. Fig. 2 is a fragmentary perspective view illustrating the details of the aforesaid counterbalance 4o device. 1 1 I Fig. 3 is a fragmentary view'in vertical section,

further illustrating the counterbalance device in operative relation to the vertically slidable door. and clarifying the manner in which the counterbalance operates.

. Fig, 4 isa fragmentary view in side elevation, illustrating a modified embodiment of my invention.

Fig. 5 is a fragmentary view in side elevation, 50 partially broken away and in vertical section, illustrating a still further modified, and preferred embodiment of a rolling counterbalance in accordance with my invention.

In present vertically operating door installan tions incorporating -a doorcounterbalancing (c1. zo-zo) mechanism of the torsion type, it iscustomary to mount the aforesaid mechanism in fixed relation to the doorheader and in a plane parallel to the header. Such installations are in general quite satisfactory, however they are characterized 8 .by the objectionable feature that since the relation of the counterbalance to the header is fixed, the operating or door elevating cables actuated by the counterbalance are only able to lift the door a certain distance, i. e., to a position where- 10 in the rollers on thelowermost door panel enter the curved portion of the track,whereupon the cables are ineffective to further the said panel due to the balancing of the component of. vertical lifting forces exerted thereon by the reaction of 15 the curved track to further vertical travel of'the door when the cables are disposed at an angle to the vertical. This usually leaves the bottom panel of the door at a substantially lower elevation than the door header, with the result that 20 the effective height of the door is decreased, or conversely, a greater door head roommust be provided in order to secure a predetermined desired effective opening. My invention corrects this difficulty byvsubstituting for the hitherto 85 known fixed. counterbalance, a counterbalance which is shiftably mounted relative to the header,

being connected to the door in the usual manner, with the result that the counterbalance is automatically shifted rearwardly during the later U period of the door operation, thereby maintaining the cable as it is trained over the front surface of the counterbalance in the vertical plane of its point of securement to the bottom door panel or section, with the result that the bottom as door sectionis drawn up the curved track as far as possible.

-The aforesaid automatically shiftable counterbalance has particular adaptability to a vertically operating door utilizing vertical tracks 40 which are inclined slightly rearwardly relative to the door jamb, as illustrated and described in the patent to Johnson No.-1,820,195, dated August 25, 1931, such rearward inclination serving to automatically initiate the rearward shifting of the the hinges thereof which travel in said tracks, iectins stop was 25 ensaseable with the heade 2 the aforesaid rollers being spaced atincreasing distances from the panels of the door vertically thereof, in order to enable a snug sealing fit of the door against the frame when the door is closed, as illustrated and described in the Johnson patent identified above. The tracks 4 include curved portions 1 which are secured by welding to angled brackets 8 bolted to the door frame adjacent the header 2 and the curved portions of the track terminate in horizontally disposed track portions 9, the latter being suitably supported at their rear ends. The door is receivable in these horizontal track portions in retracted position, as illustrated in Fig. l.

The reference numeral id designates the winding drum of the torsion counterbalance mechanism which contains a pair of supports ii for the usual torsion spring, the support shown being on a square spindle i2 extending through the end of the drum. This square spindle is received in a square aperture It in a swingable guiding and restraining arm or plate ill, thus preventing relative rotation of the shaft and arm, and the arm has an elongated slot 65 slidingly engageable with a limit pin or bolt 46 mounted on the bracket 8.

The reference numeral ill designates the counterbalance cable which is connected at one end to the lowermost door panel in the usual fashion and at the other end to drum it.

I provide a counterbalance guide tracl; in the form of a bar it? which is suitably secured to the uppermost edge of the bracket 8 and extends rearwardly in parallelism with the horizontal tracl: portion 9, being preferably bolted or riveted to the latter at It. This guide track serves as a way for a grooved counterbalance guide roller 20, which roller is freely rotatable on a circular bushing or hearing 2i provided with a square aperture (not shown) receiving the square shaft it. There is preferablya guide track i8 and guide roller 20 at each end of drum id.

By the foregoing construction, it will be apparent that substantial angular movement of the squared shaft i2 is prevented by its engagement with the arm Iii, while the grooved rollers 2d coacting with guide tracks is permit the winding drum to be freely transported rearwardly.

In operation, when the door travels up the rearwardly inclined track, the lowermost panel thereof retreats rearwardly relative to the winding drum, assuming the latter to be in its original position illustrated in Fig. 1. This causes the cable to assume a rearward lead relative to the drum and a rearwardly directed component of force to be exerted on the latter with the result that the drum shifts rearwardly on the rollers 20, and the further result that the direction of the lifting action exerted on the lowermost panel of the door is maintained substantially vertical. As the track rollers enter the curved portion i, the drum continues to shift rearwardly as illustrated in Fig. 3, and this shifting of the drum continues until the limit pin or bolt l6 reaches the end of the slot [5, at which time all portions of the door are elevated well above the header 2. The freely shiftable action of the counterbalance mount enables the door to be more readily lowered when desired.

In Fig. 4, I illustrate a modified embodiment of my invention, wherein the drum spindle I2 is mounted in angularly restrained manner in the swinging arms or plates 22 which are pivotally and fixed stops 28 on the counterbalance guide tracks I. to limit the oscillating movement oi the drum.

In operation, the embodiment of Fig. 4 is similar to that of Figs. 1 to 3, save for the fact that the drum is lifted slightly relative to the guide tracks id as it travels from front to rear and vice versa. This over-center action assures that the door will be maintained in its fully elevated and retracted position relative to the header until a definite and substantial downward force is exerted on the door,

In Fig. 5, I illustrate a. still further modified embodiment of my invention, wherein the spindle it of the drum iii is fixedly mounted on a carriage made up of a pair of spaced parallel plates 21 which overhang the counterbalance guide track it on either side thereof. A pair of carriage rollers 28 are rotatably mounted between the plates 21 on opposite sides of the drum- Ill. In this embodiment, it is obvious that the permissible movement of the counterbalance is limited only by the permissible rearward movement of the door itself, although it may be advisable to provide fixed stops 29 for the carriage on the tracks l8.

In each of the above described modifications, it should be noted that the slight rearward inclination of the tracks 6 m of substantial importance in the successful operation of the respective shiftable counterbalancing devices. It is evident that if the tracks did not incline rearwardly, the cable would be unable to come into effect in a manner to bias the winding drum rearwardly until the traclr rollers had at least entered the curved portion 6 of the tracks. It would not take a lead relative to the drum until that time. The shiftable feature does have advantages when embodied with tracks that arenot inclined, but not the full advantages obtained with the inclined tracks.

I have illustrated and described my improvements in embodiments which are very practical. I have not attempted to illustrate or describe other embodiments or adaptations as it is believed this disclosure will enable those skilled in the art to embody or adapt my improvements as may be desired.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent in:

1. In combination, a vertically operating door assembly including a pair of vertically disposed rearwardly inclined tracks having rearwardly extending horizontal top portions and an articulated door having rollers traveling in said tracks, and a counterbalance for said door, comprising a winding drum disposed transversely of the tracks, a lifting cable secured to said drum and to the door adjacent the bottom of the latter, means including torsion means for biasing the drum to elevate said cable, and means for mounting said drum for rearward shifting movement accompanying elevation of the cable and door, said cable assuming a rearward lead relative to the drum as the door travels upwardly in the inclined tracks to thereby exert a rearwardly directed force on the drum, and means for guiding said drum during the rearward shifting of the same in response to said force.

2. In combination, a vertically operating door assembly including a pair of vertically disposed rearwardly inclined tracks having rearwardly extending horizontal top portions and an articulated door having rollers traveling in said tracks,

and a counterbalance for said door, comprising a winding drum disposed transversely of the tracks, a' lifting cable secured to said drum and force.

3. In combination, a vertically operating door assembly including a pair of vertically disposed tracks and an articulated door having rollers traveling in said tracks, and a shiftable counterbalance for said dobr, comprising a winding drum disposed transversely of the tracks, a lifting cable secured to said drum and to the .door adjacent the bottom of the latter, torsion means for biasing the drum to'wind the cable thereon and elevate said door, and means for mounting said,

drum for rearward shifting movement accom-'- panying winding of the cable on the drum and door, said cable assuming a rearward lead relative to the drum during said winding to thereby exert a rearwardly directed force on the drum,

and means for guiding said drum during the rearward shifting'of the same in response to said force, J

v 4'. In combination, a vertically operating door assembly including a pair of vertically disposed tracks and an articulated door having rollers traveling in said tracks, and a shiftable counterbalance for said door, comprising a winding drum disposed transversely of the tracks, a lifting cable secured to said drum and to the door adjacent the bottom of the latter, torsion means for biasing the drum to wind the cable thereon and elevate said door, and means for mounting said drum for rearward shifting 'movement accompanying winding of the cable on the-drum and door, said cable assuming a rearward lead [818:- tive to the drum during said winding to thereby exert a rearwardly directed force on the drum, said drum shifting rearwardly in response to said force.

5. A vertically operating door assembly comprising a. door, a pair of vertically disposed and rearwar'dly inclined tracks, said door havin rollers engageable in said tracks to guide the same for vertical movement, a torsion counterbalance drum for the door, means for mountin the drum transversely of the door adjacent the door frame, said means including a rolling support forthe drum which is freely shiftable in a front to rear direction and vice versa, said drum having lifting cables-secured thereto and to the door adjacent thebottom of the latter, and means for resiliently biasing said drum in a direction to elevate the cable and door, travel of the door in said inclined track causing said cable to assume a lead relative to the drum at its point of attachment to'the door and thereby exert force'on the drum tending to shift the same rearwardly, said rearward shift maintaining a substantial vertical lifting component effective on the door,

6. A'vertically operating door assembly comprising a door, a pair of vertically disposed and rearwardly inclined tracks, said door having rollers engageable in said tracks to guide the same for vertical movement, a torsion counterbalance drum for the door, means for mounting the drum transversely'of the door adjacent the doorframe, said means including a pivoted support for the drum which is freely shiftable in a front to rear direction and vice versa, said drum having lifting cables secured thereto and to the door adjacent the bottom of the latter, and means for'resiliently biasing said drum in a direction to elevate the cable and door, travel of the door. in said inclined track causing said cable to assume a lead relative to the drum at its point of attachment to the door and thereby exert force on the drum tending to shift the same rearwardly,said drum and support therefor shifting rearwardly in response to said force.

'7. Counterbalancing device for a vertically operating door, comprising a torsion counterbalance drum disposed in-a plane parallel to the door,

, lifting cables secured to said drum and door.

and means for mounting the drum for lateral movement in response to vertical actuation of I! the door, comprising a carriage supporting the drum, a fixed trackprojecting rearwardly relative to the door frame, and drum guide rollers rotatably mounted in said carriage and traveling on said track, said carriage and drum being shifted laterally by reason of the lateral lead assumed by the cable relative to the drum during operation of the door.

8. Counterbalancing device for a vertically operating door, comprising a torsion counterbalance 80 drum disposed in a plane parallel to the door, lifting cables secured to said drum anddoor.

and means for mounting the drumfor lateral movement in response to vertical actuation of the door, comprising a carriage supporting the I ance drum disposed in a plane parallel to the door, lifting cables secured to said drum and door, and means for mounting the drum. for lateral movement in response to vertical actuation of the Y door, comprising a carriage supporting the drum, a laterally fixed guide member, and guide means von said carriage coasting with said first named guide member, said carriage and drum being shifted laterally by reason of the lateral lead assumed by the cable relative to the drum during operation of the door.

- 10. A vertically sliding door-assembly including a torsion drum having a cable secured thereto and to a vertically sliding door guided in a track, and means for mounting said drum for laterally shifting movement inresponse to movement'of the door, comprising a fixed bracket, and an arm swingably and shiftably mounted on said bracket and carrying said drum, the mounting of the arm on the bracket being adapted to limit the lateral shifting of the arm and drum, the door cable biasing the drum laterally in. the move-. ment of the door in. the track.

11. A vertically sliding door assembly including a torsion drum having a cable secured thereto and to a vertically sliding door guided in a track and means for mounting said drum .for laterally shifting movement in response to movement of I on, said arm carrying said drum during movement thereof laterally in'response to movement of the door in the track;

12. In a vertically acting door assembly, the combination of an articulated door, tracks therefor comprising rearwardly inclined vertical portions, horizontal top portions and rearwardly curved portions Joining the vertical and horizontal portions, 9. counterbalance drum having torsion means housed therein, means for supporting said drum for lateral shitting movement, and a counterbalancing cable secured to the lower end of the door and to said drum, whereby the drum will automatically shift on its support by the shitting of the lead of the cable resulting from the opening. and closing movements of the door.

13. In a vertically acting door assembly, the combination of an articulated door, tracks therefor comprising vertical portions, horizontal top portions and rearwardly curved portions Joining the vertical and horizontal portions, a counterbalance drum provided with torsion means,

means for supporting said drum for lateral shitting movement, and a ooimterbalancing cable eecured to the lower end of the door and to said drum, whereby the drum will automatically shiit on its support by the shifting of the lead of the cable resulting from the opening and closing movements of the door.

14. The combination in a vertically acting door assembly of a door, tracks thereior provided with vertical portions and horizontal portions with intermediate rearwardly curved portions, a counterbalance drum mounted in a plane above the vertical portion or the track for shifting movement from front to rear, and a cable connected to the lower end of the door and windable on said 'drum, said drum being free to shift to maintain the angular relation of the cable relative to the drum HERBERT CADY BLODGETI. 

